AC Relay Switch, any recommendation

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djoshi
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Posted by djoshi: Thu. Feb 26, 2009 - 12:16 PM
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Hi All

Please can some one either recommend or guide me a good Relay manufacture, that is cheap and aslo very good.

I am thining about making a relay timer , which controls the on and off a power source 120-240V. Example i might want my lights to switch on at 7:00, the AVR would tell the Relay and Relay would switch it on.

I would like a relay which is small compared to somthing that is blucky.

I know there are many out there, but which ones would you say are best and safe as i am playing around with 240V.

Regards

DJ

Thanks

Regards

DJ

Tags:

Learning and Information, General Electronics
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Kartman
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Posted by Kartman: Thu. Feb 26, 2009 - 01:01 PM
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How many amps do you want to switch? How cheap do you want it? What attributes do you consider to be good? What do you consider to be small? What I consider best, may not meet your other criteria. As for safe, there is standards for safety - choose a relay that has compliance with your country's requirements.

You can't half tell I'm an engineer - qualify and quantify.

As to which relay, I'd start with Omron,NAIS...make Google your friend. Most of the cheaper Chinese relays are similar to the brand name parts ( maybe from the same factory??)

At a pinch, I'd probably choose an Omron G2R series, or maybe a G5R, G6R... the G2R are quite cheap in quantity and second sourced by many.

As to why you would want to design a timer when you can buy these items already cheaper than what you can make them for.

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djoshi
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Posted by djoshi: Thu. Feb 26, 2009 - 01:47 PM
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I would require about 15amps, as i belive that is the amps max of power socket.

Price wise may be $0.50 or less, would i be right in saying that

When i say good, i mean then the mechnical to be strong anfd long lasting.

And size, wise small as possible. I presume all manufacture make a standard size. But ill read up on that.

Well i go garden lights, that i want to control at night a certain light switchs on. So i prefer to make it, as i got some time in my hands

Regards

DJ

Thanks

Regards

DJ

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johnrk
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Posted by johnrk: Thu. Feb 26, 2009 - 02:35 PM
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Hi DJ,

Quote:
Price wise may be $0.50 or less, would i be right in saying that

15 amps switching at 240 volts for 50 cents!! If you find that, let me know!! Perhaps I am misunderstanding your vision but, I think 50 cents for such a relay is unrealistic!

John

Just some guy

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djoshi
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Posted by djoshi: Thu. Feb 26, 2009 - 02:40 PM
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To be honest i am not sure. Cheaper the better.

I remember using some really when i was in college, mabe they were cheap, but less current.

I need to do some reasearch on this subject.

But is there a pericular type i should use such as latching type.

I have noticed many rquire 12V to operate, this is not a problem, all i do is a AC/DC and regulate a 12V. But once i supply 12 does it have to be continious or just pulse.

Regards

Dj

Thanks

Regards

DJ

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oddbudman
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Posted by oddbudman: Thu. Feb 26, 2009 - 03:10 PM
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djoshi,

The 12V needs to be continuous.

With the knowledge you seem to have you really should just get hold of a relay or two and have a play to figure out what its all about.

With the knowledge you have about relays currently, you really should not consider switching a 110/240V product. Your likely to do some damage to either the relays our yourself.

Start out with a low voltage source and go from there.

oddbudman

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djoshi
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Posted by djoshi: Thu. Feb 26, 2009 - 03:15 PM
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Dear oddbudman

Thanks for the advice.

I wouldent go on to 120/240V, straight away. I still need to make some sort of 12V driver, which be controlled via an AVR.

What thing should i taken in account when playing with 120-240V.

I no for sure not to touch the circuit once it got 120/240V, switch it off before making an adjustments.

Am i correct in saying that the LIVE wire must be connected via the relay, to switch on and off applicance such as light lamps.

Regards

DJ

Thanks

Regards

DJ

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david.prentice
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Posted by david.prentice: Thu. Feb 26, 2009 - 03:40 PM
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Quote:
I remember using some really when i was in college, mabe they were cheap, but less current.

Did you go to any classes while you were at college ?

Perhaps Spelling or Physics.

David.

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djoshi
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Posted by djoshi: Thu. Feb 26, 2009 - 03:52 PM
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Sorry I was on my mobile phone, but not now i am on my PC. Was in rush as well.

Sorry

Thanks

Regards

DJ

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Kartman
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Posted by Kartman: Thu. Feb 26, 2009 - 10:53 PM
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For a start you should make yourself aware to the elctrical wiring rules of your country. For the U.S.A it is NEC. In most countries you can purchase the standard for a reasonable price. This outlines the legal and technical requirements.
What do you need to know about 120/240Vac? Well, it can kill you is the first thing. You need to ensure the wiring is adequately sized and insulated. You need to be aware of earthing - especially when you have a metallic enclosure. You need to be aware of mechanical protection for the wires - if someone trips over the power cord to your box that the live wires don't pull out and electrocute you. The Omron G2R relay I mentioned is available in a 16A version which is a popular choice for what you're doing. If you want to buy 1000's of relays, 50cents is a viable price, I pay over $1AUD for 1000 off of the 16A G2R, probably more now the dollar has moved.

12V and 24Vdc relays tend to be cheaper as they are more popular. You'll need a mosfet or transistor on the AVR in order to switch the relay.

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